A surround-sound system can emit sounds from a plurality of speakers disposed in front of and at the rear of a listener so as to provide the listener with a sound rich in presence. In the surround-sound system, however, speakers must be disposed in front of and at the rear of the listener. For this reason, the surround-sound system is not adequate to a small room. In addition, there is a problem that signal lines for supplying an output signal of each channel from an audio amplifier to both the speaker disposed in front of the listener and the speaker disposed at the rear of the listener are obstructive because the signal lines must be put around in the room. As techniques to solve these problems, Patent Documents 1 and 2 disclose techniques which are used to dispense with rear speakers in such manner that a speaker array with high directivity is disposed in front of a listener to thereby make sound beams which are output from this speaker array and which are reflected by walls of a sound space arrive at the listener.
Patent Document 1: JP-A-6-205496
Patent Document 2: JP-A-2004-179711